Machine for producing circular products

ABSTRACT

A machine for producing circular products such as bottoms and lids of casks comprising a machine base, a blank feeding station, a blank sawing station, a blank chamfering station and a blank positioning station provided on said base in a circumferentially spaced relationship, a vertical main drive shaft rotatably mounted in said base, blank support means fixedly mounted on said drive shaft and having a plurality of spaced blank support discs, blank holding-down means fixedly mounted on said drive shaft and having a plurality of arms each having a downwardly extending shaft on which a blank holding-down member is journalled in opposition to the associated one of said support discs to hold a blank therebetween.

United States Patent Sempei [75] Inventor: Suzuki Sempei, Hamamatsu, Japan [73] Assignee: Suntory Limited, Osaka, Japan [22] Filed: Mar. 11, 1974 [21] 'Appl. No.: 450,150

[30] Foreign Application Priority Data Mar. 13, 1973 Japan .7 48-29246 [52] 11.5. CI. 147/36 [51] Int. Cl B27h 3/04 [58] Field of Search 147/36, 38, 40', 144/1 R, 144/1 D. 4, 21

[56] References Cited UNITED STATES PATENTS 488,167 12/1892 Kane n 147/40 720,628 2/1903 Shaw 147/36 1 1 June 17, 1975 Primary ExaminerGranville Y. Custer, Jr. Attorney, Agent, or Firm-Holman & Stern 5 7 1 ABSTRACT A machine for producing circular products such as bottoms and lids of casks comprising a machine base a blank feeding station, a blank sawing station, a blank chamfering station and a blank positioning station provided on said base in a circumferentially spaced relationship, a vertical main drive shaft rotatably mounted in said base, blank support means fixedly mounted on said drive shaft and having a plurality of spaced blank support discs, blank holding-down means fixedly mounted on said drive shaft and having a plurality of arms each having a downwardly extending shaft on which a blank holding-down member is journallcd in opposition to the associated one of said support discs to hold a blank therebetween.

8 Claims, 5 Drawing Figures 1 MACHINE FOR PRODUCING CIRCULAR PRODUCTS BACKGROUND OF THE INVENTION This invention relates to a machine for producing circular products such as cask bottoms and lids.

There have been proposed a variety of systems for producing circular products such as cask bottoms and lids and in any of the prior art systems, separate machines which are designed to perform different produc tion steps in the production operation of the circular products, respectively and installed in different areas in a production plant. Thus, after one production step has been completed on a blank in one machine adapted to perform a particular step, the blank has to be manually transferred to another machine adapted to perform a second different step and so on consuming a great amount of valuable time. Therefore, the operation in the prior art systems of the above-type is inefficient and since the various machines have to be installed at different areas in a particular production plant, a great deal of floor space is required in the plant for the installation of the machines.

SUMMARY OF THE INVENTION Therefore, the present invention provides a compact machine of the above type for producing circular products such as cask bottoms and lids which can effectively eliminate the above-mentioned disadvantages inherent in the prior art systems of the above-type.

One object of the present invention is to provide a machine of the above type which can perform material feeding, sawing, chamfering and positioning operations in succession.

Another object of the present invention is to provide a machine of the above-type for producing circular products which generally comprises a machine base, a blank feeding station, a blank sawing station, a blank chamfering station and a blank positioning station on the base, a cross-shaped blank support member rotatably mounted on the base and having a plurality of blank support discs, a cross-shaped blank holdingdown assembly rotatably mounted on the base above the support member and having a plurality of blank holding-down members for pinching blanks in cooperation with the associated support discs respectively, said blank support and holding-down members being adapted to be in succession disposed in the feeding, sawing, chamfering and positioning stations, a rotary band saw positioned in the sawing station for sawing the blank to a desired diameter intermediate product and a rotary blank chamfer cutter positioned in the chamfering station for chamfering the intermediate product to a desired complete circular product.

According to the present invention, a material blank is in succession fed, sawn, chamfered and positioned as the blank is in succession positioned in the feeding, sawing, chamfering and positioning stations. And the sawing and chamfering operations are simultaneously performed on different blanks positioned in the sawing and chamfering positions, respectively by the rotating band saws and cutter positioned in the sawing and chamfering stations, respectively while the blanks are held between the holding-down members and support discs when the members and discs are positioned in the stations.

The above and other objects and attendant advantages of the present invention will be more readily apparent to those skilled in the art from a reading of the following detailed description in conjunction with the accompanying drawings which show one preferred embodiment of the invention for illustration purpose only, but which do not limit the scope of the same in any way.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view of one preferred embodiment of a machine for producing circular products constructed in accordance with the present invention;

FIG. 2 is a top plan view of said machine;

FIG. 3 is a cross-sectional view taken along substantially the line A A of FIG. 1;

FIG. 4 is a cross-sectional view taken along substantially the line B B of FIG. 2; and

FIG. 5 is a vertically sectional view of detent means positioned in the positioning station of the machine.

PREFERRED EMBODIMENT OF THE INVENTION The present invention will be now described referring to the accompanying drawings which show one preferred form of a machine for producing circular products embodying the present invention. The machine comprises a base I from which a rotary main drive shaft 2 extends uprightly and the lower end of the shaft is suitably journalled in the base. Disposed about and equally spaced from the upright main drive shaft 2 on the base I are a material blank feeding station A where an optical detector 3 which detects the center of a material blank is provided, a sawing station B, a chamfering station C and a positioning station D. A crossshaped holding-down assembly E is fixedly mounted on the main drive shaft 2 in a coaxial relationship to the latter for unison rotation and has four radially extending arms 19 the free or outer ends of which journal blank holding-down members 18 which extend downwardly from the arms 19, respectively. A worm wheel 4 is fixedly mounted on the main drive shaft 2 below the cross-shaped holding-down assembly E and in engagement with a worm 7 which is in turn suitably supported on a shaft connected to and adapted to be driven from an intermittently driven feed motor 5 through a change gear 6 positioned therebetween. Thus, the worm wheel 4 is rotated from the feed motor 5 through the change gear 6, shaft and worm 7 to thereby rotate the main drive shaft 2.

A cross-shaped blank support member 8 is fixedly mounted on the main drive shaft 2 between the crossshaped holding-down assembly E and worm wheel 4 and has four radially extending arms 8' at the free end of each of which a rotary blank support disc 9 is journalled.

Since all the four blank support discs 9 are identical, description will be had on only one of the support discs 9 with the understanding that the same will be applicable to the other three discs. The support disc 9 has a coaxial shaft 10 extending downwardly therefrom and the shaft is provided adjacent to the lower end thereof with a detent hole 12 for the purpose to be described hereinafter. An annular abutment ring 14 is disposed on the shaft 10 at the lower reduced diameter end of the shaft and has an annular flange 14' having grooves 15 on the under surface for engaging a vertically movable shaft 13 of which description will be made hereinafter. The annular ring 14 also has a key way for receiving a key 16 which connects the ring to the shaft 10.

The shaft 10 is provided with an annular flange 10' above the reduced diameter lower end in opposition to and spaced from the flange 14' of the ring 14 and a coiled spring 17 is disposed between the flanges l and 14' for normally biasing the ring 14 downwardly so that the engagement between the shafts l0 and 13 will be maintained when rotation is transferred between the shafts and 13.

Each of the holding-down members 18 is movable between a first or lower position in which the member holds a blank to be processed in place in cooperation with the associated blank support disc 9 and a second or upper position in which the member is spaced from the support disc 9 and releases its holding force from the blank. Since all the four arm and holding-down member assemblies are also identical, description will be made on only one of the assemblies with the under standing that the same will be applicable to the other three assemblies. The holding-down member 18 is journalled in the lower portion ofa hollow shaft 21 for vertical movement along the shaft by means of a bearing 18'. For the vertical movement of of the holding-down member 18, the outer end portion of the support arm is formed with a hollow construction to define a hydraulic cylinder 20 therein and the hollow shaft 21 has an integral piston 21' received in the cylinder 20 for vertically-reciprocal movement. When the piston 21' has hydraulic pressure applied on the upper surface thereof from a suitable hydraulic pressure source (not shown) the piston is moved downwardly so as to move the holding-down member 18 downwardly and when hydraulic pressure is applied on the under surface of the piston 21' from the hydraulic pressure source, the piston is moved upwardly so as to move the holdingdown member 18 upwardly.

Blank Feeding Station A A material blank to be processed to a circular prod uct may be a wood blank W for the bottom or lid of a cask, for example and the blank is manually fed into the machine at the blank feeding station A. The blank should be accurately centered on the support disc 9 disposed in the feeding station A. For the purpose, the above-mentioned optical detector 3 has an electric lamp therein to detect whether the blank has been centered on the support disc 9 disposed in the blank feeding station A. The optical detector 3 is electrically connected to a suitable electric means (not shown) and mounted on a horizontal support frame 24 which is in turn supported at the opposite ends at the upper ends of a pair of opposite and spaced upright colums 23, 23 which are supported at the lower ends in support brackets 22, 22 mounted on and horizontally extending from the base 1. The blank bears a mark in the center of the obverse surface to be lighted by the lamp of the detector 3. When the mark on the blank is in registry with the light from the lamp, it is assumed that the blank has been accurately centered on the support disc 9. On the other hand, when the center mark on the blank is not in registry with the light of the lamp, it is assumed that the blank is not centered on the disc and in such a case, the position of the blank is adjusted until the center mark comes into registry with the light of the lamp.

Sawing Station B In the sawing station B, there is provided the abovementioned vertically reciprocal shaft 13 in a position to be positioned just below the blank support disc 9 which is then disposed in the sawing station B. The shaft 13 is journalled in a bearing 28 which is integral with a piston 27 which is in turn movably received in a cylinder 26 suitably provided in the machine base 1. The upper end face of the shaft 13 is provided with grooves 29 which are complementary to and adapted to engage the lands 15 in the under surface of the flange 14' of the annular ring 14 and the lower end of the shaft 13 has a toothed wheel 30 thereon. The toothed wheel 30 is in engagement with a pinion 33 on a shaft 32 the other end of which has a grooved pulley 33'. An endless chain (shown with the chain line in FIG. 3) passes over the pulley 33 and a pulley 31' on the output shaft of a continuously driven common motor 31 so that the shaft 13 is rotated from the motor 31 through the abovementioned transmission arrangement.

An external slide 34 is provided on the side of the machine base 1 adjacent to the sawing station B and has track means 34 on the upper surface of the slide. A U-shaped carrier 35 is guided along the track means 34 for slidable movement toward and away from the machine base 1. The upper and lower parallel legs of the Ushaped carrier 35 rotatably support laterally extending shafts 39 and 37' in a common vertical plane, respectively and upper and lower wheels 38 and 37 are mounted on the shafts 39 and 37', respectively, for rotation together with the respectively associated shafts. An endless band saw 36 is passed over the wheels 38 and 37 and the lower wheel shaft 37' is operatively connected through a pulley belt drive arrangement to a continuously driven motor 40 which is also disposed outside of the machine base 1 adjacent to the sawing station B. Thus, the lower wheel 37 is a drive wheel and the upper wheel 38 is a driven wheel. The shaft 39 of the upper wheel 38 is journalled in an adjustable arm (not shown) which is mounted on the upper leg of the Ushaped carrier 35 in such a manner that the vertical distance between the axes of the upper and lower wheel shafts 39 and 37' can be varied so as to maintain the tension on the band saw 36 at a proper value for a particular material blank. A first guide rod 41 extends downwardly from the inner or free end of the upper leg of the Ushaped carrier 35 and a second guide rod 41' extends upwardly from the free or inner end of the lower leg of the same Ushaped carrier in a common vertical plane. The free or inner ends of the upper and lower guide rods 41 and 41' are spaced from each other and provided with guide means 42 and 42', respectively. Thus, the material blank (not shown in the sawing station B) is sawn to a predetermined diameter intermediate product by the section of the band saw 36 which passes through the space between the upper and lower guide means 42 and 42'.

Chamfering Station C In the Chamfering station C, there is provided a vertically reciprocal shaft 13 similar to the corresponding shaft 13 as described in connection with in the sawing station B and has grooves 29 at the upper end face for engaging the mating lands 15 in the under surface of the flange 14' of the ring 14 on the shaft 10 for the sup port disc 9 disposed in the chamfering station C. The

shaft 13 is journalled in a bearing member 28 having an integral piston 28 received in a cylinder 26 which is provided in the base 1 and suitably communicating with a hydraulic pressure source (not shown). When the lower surface of the piston 28 has hydraulic pressure applied from the hydraulic pressure source to move upwardly, the shaft 13 is also moved upwardly to bring its grooves 29 into engagement with the mating grooves in the ring 14 on the shaft of the support disc 9 then disposed in the chamfering station C. As described in connection with the sawing station B, the shaft 13 is provided at the lower end with a toothed wheel 30 which is in engagement with a pinion 33 which is in turn splined to a shaft 32 the other end of which has a pulley 33' thereon. The endless belt which is passed over the pulley 31' operatively connected to the output shaft of the motor 31 (the belt, pulley 31 and motor are common to the sawing station B) is also passed over the pulley 33 in the chamfering station C. The belt is also passed over a pulley positioned between the pulley 33' in the sawing station B and the pulley 31 operatively connected to the output shaft of the common motor 31. Thus, when the shaft 13 is moved upwardly to engage the shaft 10 of the support disc 9 then disposed in the chamfering station C by means of the mating grooves 29 and lands of the shafts l3 and flange 14 on the shaft 10 of the support disc 9, the rotation of the shaft 13 is effected from the continuously driven common motor 31 through the abovementioned transmission arrangement relative to the bearing 28. In the chamfering station C, there is also provided a chamfering cutter 43 in the position for chamfering the blank pinched between the rotating holding-down member 18 and support disc 9 then positioned in the station C. The chamfering cutter 43 is fixedly mounted on the lower end portion ofa vertical shaft 47 which is in turn journalled in a hollow arm 46 which has the lower end journalled in the machine base 2. A upright column 45 extends upwardly through the arm 46 in parallel to and spaced from the shaft 47 to further journal the arm 46. The lower end of the column 45 is connected to one end of an arm 48 the other end of which is operatively connected to the piston rod 50 in a cylinder 49 which is in turn pivoted to the machine base 2. The upper end of the shaft 47 supports a grooved pulley 55 and an endless belt 52 is passed over the pulley 55 and a pulley 52 mounted on the output shaft of a continuously driven motor 51 mounted on one side of the above-mentioned support arm 46. Thus, the cutter 43 is continuously rotated from the motor 51 through the above-mentioned transmission arrangement to perform its chamfering operation on the blank W pinched between the holding-down member 18 and the support disc 9 then disposed in the chamfering station C as seen in FIG. 4.

A support plate 53 is secured to the bottom of the support arm 46 and has a recess in the upper surface. An annular holding-down plate 53 is provided to define a space in cooperation with the recess for receiving an eccentric roll 54 which abuts against the rotating support disc 9 and along which the cutter 43 follows. Numeral 56 denotes a spring-loaded cutter change handle which has a stop 57 thereon and is normally urged inwardly by a spring (not shown) which is disposed on the shank of the handle in a casing secured to the arm. When the cutter 43 is desired to be replaced by a different size or style cutter, the handle 56 is pushed inwardly until the stop 57 enters the spring casing and at the same time, the inner end of the handle shank is received in a hole 47' in the shaft whereupon the rotation of the shaft 47 is stopped. Thereafter, the cutter 43 can be removed from the arm 46 and replaced by a different cutter.

Positioning Station D In the positioning station D, there is provided a detent 11 in a position to be positioned just below the shaft 10 of the support disc 9 then disposed in the positioning station D to be driven into the detent hole 12 in the shaft 10 by the piston (not shown) in a vertical cylinder 26 fixedly mounted on the machine base 1.

In operation, it is assumed that the detent 11 is received in the hole 12 in the shaft 10 of the support disc 9 then disposed in the positioning station D, the holding-down members 18 in all the stations are in their inoperative position or in their upper position away from the associated support discs 9 and the vertical shafts 13 are in their lower position disengaged from the associated shafts 10 in all the stations and therefore, the machine is in its rest position with no blanks placed on the support discs 9. When the machine is to be operated. a blank W is manually placed on the support disc 9 then disposed in the feeding station A and the detector 3 is energized to center the blank W on the disc 9. After the blank W has been properly centered on the support disc 9, hydraulic pressure is applied on the upper surface of the piston 20 within the arm 19 disposed in the feeding station A to move the piston 20 downwardly so as to move the holding-down member 18 journalled on hollow shaft 21 integral with the piston 20 downwardly toward the support disc 9 whereby the blank W is pinched between the holding-down member 18 and support disc 9. After the blank W has been firmly held between the holding-down member and support disc 9 in the feeding station A, the limit switch (not shown) associated with the feeding station A automatically and momentarily operates to drive the intermittently driven feed motor and at the same time, to retract the detent 11 from the hole 12 in the shaft 10 of the support disc 9 whereupon the main drive shaft 2 is rotated to rotate the arms 8', 9 and their associated moving parts to the sawing station B so as to dispose the blank W in the sawing station B. When the blank W has been disposed in the sawing station B, the limit switch again operates momentarily to stop the feed motor 5 and at the same time, the detent 11 in the positioning station D is advanced into the hole 12 in the shaft 10 of the arm 9 disposed in the positioning station D to stop the operation of the machine. The limit switch (not shown) associated with the sawing station B momentarily operates to cause the hydraulic pressure source (not shown) associated with the sawing station B to apply hydraulic pressure on the under surface of the piston 26 of the blank holding unit (holding-down member and support discs) disposed in the sawing station B so as to move the piston and bearing assembly 26 and 28 upwardly within the cylinder 26 to thereby move the shaft 13 upwardly until the grooves 29 in the shaft 13 engage the mating grooves 15 in the annular ring 14 on the shaft 10 in the blank holding unit disposed in the sawing station B whereupon the rotation of the continuously driven common motor 31 is transmitted to the support disc 9 through the above-mentioned transmission arrangement. Thus, the blank W held between the rotating holding-down member 18 and support disc 9 of the blank holding unit disposed in the sawing station B is rotated. While rotating, the blank W is sawn to a desired or predetermined diameter intermediate product by the rotating band saw 36. After the blank W has been sawn to the desired diameter, the limit switch associated with the intermittently driven feed motor momentarily operates to rotate the main drive shaft 2 so as to rotate the blank holding unit now disposed in the sawing station B to the chamfering station C. The detent 11 is again advanced into the hole 12 in the shaft 10 of the support disc 9 of the blank holding unit disposed in the positioning station D to hold the blank holding unit having the swan intermediate product held therein in the chamfering station C so as to position the blank in the chamfering position. The means for actuating the detent 11 comprises a piston 59 received in a cylinder 60 which has an integral hollow guide 58 along which the detent 11 moves. When the detent 11 is to be advanced into the detent hole 12, hydraulic pressure is applied on the under surface of the piston 59 from a suitable hydraulic source not shown On the other hand. when the detent 11 is retracted from the hole 12, such hydraulic pressure is applied on the upper surface of the piston 59. After the blank W has been positioned in the chamfering station, the detent 11 is again retract ed from the hole 12 in the shaft 10 of the blank support disc 9 disposed in the positioning station and at the same time, the limit switch (not shown) associated with the chamfering station C momentarily operates to move the shaft-piston assembly 21,21 and in consequence, the holding-down member 18 downwardly and at the same time, to move the pistonbearing assembly 27,28 and in consequence, the shaft 13 upwardly so as to bring the shaft 13 into engagement with the shaft 10 in the chamfering station C. Thus, the rotation of the continuously driven common motor 31 is transmitted to the arm 9 through the abovementioned transmission arrangement to thereby rotate the blank W held in the blank holding unit disposed in the chamfering station C. While rotating, the blank or intermediate product is chamfered by the rotating cutter 43. The above-mentioned operation sequence may be repeated to make the circular product producing operation in the illustrated machine continuous. In this way, the blank feeding, sawing, chamfering and positioning operations are effected by the operation of the limit switches associated with the various stations.

From the foregoing description of the operation in the illustrated machine, it will be understood that the blanks held in the blank holding units disposed in the sawing and chamfering stations B and C are simultaneously sawn and chamfered, respectively and thus, the entire operation can be continuously performed with high efficiency.

It will be understood that variations and modifications of the invention may be made without departing from the scope of the invention. It is also to be understood that the scope of the invention is not to be interpreted as limited to the specific embodiment disclosed herein, but only in accordance with the appended claims when read in light of the foregoing disclosure.

What is claimed is:

1. A machine for producing circular products comprising a base having a blank feeding station, a blank sawing station, a blank chamfering station and a blank positioning station which are positioned on said base in a circumfcrentially spaced relationship, a vertically extending main drive shaft intermittently rotatably mounted on said base, blank support means fixedly mounted on said main drive shaft and having a plurality of equally spaced support discs, a blank holding-down means fixedly mounted on said main drive shaft above said blank support means and having a plurality of spaced blank holding-down members in opposition to said support discs, respectively and adapted to hold blanks in cooperation with their respective associated ones of said support discs, said holding-down members and support discs being adapted to be in succession disposed in said feeding, sawing, chamfering and positioning stations, vertically movable rotation transmission means positioned in each of said sawing and chamfering stations for engaging each of said blank support discs to transfer rotation to the support disc when the support disc is disposed in each of the sawing and chamfering stations, a rotational band saw positioned in said sawing station for sawing engagement with a blank held by the holding-down member and associated support disc when the member and disc are disposed in the sawing station, a rotational chamfering cutter positioned in said chamfering position for chamfering engagement with the sawn blank from said sawing station when the holding-down member and support disc holding the sawn blank therebetween are disposed in the chamfering station and detent means positioned in said positioning station to engage the holdingdown and support disc in said positioning station so as to stop the movement of said holding-down and support discs disposed in the feeding, sawing, chamfering and positioning to thereby allow said band saw and cutter to perform their sawing and chamfering operations on the blanks positioned in these stations.

2. The machine as set forth in claim 1, in which said blank support means comprises a cross-shaped support assembly fixedly mounted on said main drive shaft and having four said support discs extending from the center of the assembly.

3. The machine as set forth in claim 1, in which said blank holding-down means comprises a cross-shaped assembly fixedly mounted on said main drive shaft and having four arms extending radially from the center of the assembly, each of said arms rotatably supporting one of said blank holding-down members.

4. The machine as set forth in claim 3, in which each of said arms has a hollow shaft depending therefrom and said blank holding-down member is rotatably supported on said hollow shaft.

5. The machine as set forth in claim 1, in which said rotation transmission means comprises a vertically reciprocal and rotational shaft positioned below each of said sawing and chamfering stations for engaging and disengaging from said blank support disc when the arm is positioned in each of the sawing and chamfering stations.

6. The machine as set forth in claim 1, in which said detent means comprises a vertically movable detent positioned in said positioning station and a detent hole in the shaft of each of said support discs.

7. The machine as set forth in claim 1, in which an optical detector is provided in said blank feeding station for detecting the center of a blank disposed on the blank support disc positioned in the feeding station.

8. The machine as set forth in claim 1, further including means for adjusting the tension of said band saw. 

1. A machine for producing circular products comprising a base having a blank feeding station, a blank sawing station, a blank chamfering station and a blank positioning station which are positioned on said base in a circumferentially spaced relationship, a vertically extending main drive shaft intermittently rotatably mounted on said base, blank support means fixedly mounted on said main drive shaft and having a plurality of equally spaced support discs, a blank holding-down means fixedly mounted on said main drive shaft above said blank support means and having a plurality of spaced blank holding-down members in opposition to said support discs, respectively and adapted to hold blanks in cooperation with their respective associated ones of said support discs, said holding-down members and support discs being adapted to be in succession disposed in said feeding, sawing, chamfering and positioning stations, vertically movable rotation transmission means positioned in each of said sawing and chamfering stations for engaging each of said blank support discs to transfer rotation to the support disc when the support disc is disposed in each of the sawing and chamfering stations, a rotational band saw positioned in said sawing station for sawing engagement with a blank held by the holding-down member and associated support disc when the member and disc are disposed in the sawing station, a rotational chamfering cutter positioned in said chamfering position for chamfering engagement with the sawn blank from said sawing station when the holdingdown member and support disc holding the sawn blank therebetween are disposed in the chamfering station and detent means positioned in said positioning station to engage the holding-down and support disc in said positioning station so as to stop the movement of said holding-down and support discs disposed in the feeding, sawing, chamfering and positioning to thereby allow said band saw and cutter to perform their sawing and chamfering operations on the blanks positioned in these stations.
 2. The machine as set forth in claim 1, in which said blank support means comprises a cross-shaped support assembly fixedly mounted on said main drive shaft and having four said support discs extending from the center of the assembly.
 3. The machine as set forth in claim 1, in which said blank holding-down means comprises a cross-shaped assembly fixedly mounted on said main drive shaft and having four arms extending radially from the center of the assembly, each of said arms rotatably supporting one of said blank holding-down members.
 4. The machine as set forth in claim 3, in which each of said arms has a hollow shaft depending therefrom and said blank holding-down member is rotatably supported on said hollow shaft.
 5. The machine as set forth in claim 1, in which said rotation transmission means comprises a vertically reciprocal and rotational shaft positioned below each of said sawing and chamfering stations for engaging and disengaging from said blank support disc when the arm is positioned in each of the sawing and chaMfering stations.
 6. The machine as set forth in claim 1, in which said detent means comprises a vertically movable detent positioned in said positioning station and a detent hole in the shaft of each of said support discs.
 7. The machine as set forth in claim 1, in which an optical detector is provided in said blank feeding station for detecting the center of a blank disposed on the blank support disc positioned in the feeding station.
 8. The machine as set forth in claim 1, further including means for adjusting the tension of said band saw. 